1. Field of the invention
The invention relates to a remote control hand apparatus for controlling several functions of one or more modules which to that end are coupled to this hand apparatus via a transmission means (wireless or wired). Said modules may consist of a TV receiver, a video recorder, a teletext decoder, an audio amplifier, an audio tuner, a compact disc player etc., but alternatively a door, a lighting system etc.
2. Description of the Prior Art
As is generally known, such a hand apparatus has a plurality of control keys forming the operable portions of switches which are usually arranged in a matrix structure and connected to a control circuit which determines whether a key has been pushed and which one. It then produces a group of pulses which are characteristic of the relevant key and are applied to a transmitter circuit. In said transmitter circuit this group of pulses is modulated on an appropriately chosen carrier signal, (preferably an infrared signal) and thereafter transmitted to the, or one of the modules, preferably via a wireless transmission channel.
To provide a distinction between the different types of modules, the hand apparatus may be provided with a separate set of control keys for each module. Apart from the fact that the hand apparatus would then become impermissibly large, it would also become very expensive because of the large number of keys. To obviate these disadvantages, European Patent Application No. 0120345 discloses a hand apparatus comprising only a limited number of keys, but with which all the functions of a plurality of modules can still be controlled. For that purpose this hand apparatus can be set to a plurality of modes, for example a selection mode and a plurality of module means. In the selection mode one module is assigned to each key or to a number of keys, that is to say that if now a given key is operated, the hand apparatus is adjusted to a module mode and the user accesses that module (for example the TV-receiver) assigned to the operated key. In this module mode the several keys are given control functions which are typical for the control of that module. The function a predetermined key can control consequently differs from module-mode to module-mode. Consequently, the keys of this prior art hand apparatus are multifunctional. To inform the user which function is assigned to which key at a given instant, each key is assigned a key display element on which the actual control function of the key is displayed, for example in the form of a symbol. To achieve all of this, this prior art hand apparatus comprises a control circuit in the form of a microcomputer to which both the keys and the key display elements are coupled. With this microcomputer it is also possible to control a further display for displaying certain informative texts. Therefore, this last mentioned display will be referred to as the information display.
This prior art hand apparatus has indeed a particularly conveniently arranged control panel, but the key display elements are required to be of a large size such that the actual control function can be shown clearly enough. Furthermore, the additional information display, and also all of the display driver circuits, require a considerable amount of space so that in practice this hand apparatus would become impermissibly large. In order to keep the dimensions of this hand apparatus sufficiently small the number of control keys is greatly limited. The result thereof is that several functions can only be controlled after a number of other keys have been operated. Thus, when the hand apparatus is in one module it must, for example, be first adjusted to the selection mode before the user can get access to another module.